Thermodynamic Characterization of Coolants
The correct acquaintance with the thermo-physical properties of gases is the primary ingredient in the recipe for successful design and operation of Joule-Thomson cry coolers. This is particularly true of the class of cry coolers that utilize the throttle effect with real gas properties, and the extent to which their deviation from those of an ideal gas provides the driving potential for the cryocooling process. The gas as a coolant is much more than simply a working media, as for instance in case of pulse tube cry coolers, where real gas properties play a minor role. In the service of Joule-Thomson cry coolers, each particular gas has its own unique characteristics that cannot be replaced without significant impact on performance. Furthermore, the thermo physical features of the selected operating gas directly influence the construction and possible modes of operation.